Portable electronic devices having radio reception or radio communication capabilities typically include one or more antenna sub-assemblies. Examples of such devices include, but are not limited to, mobile phones, pagers, radio sets, Personal Digital Assistant (PDA) and gaming devices capable of radio communications, satellite navigation devices and television receivers. Antennas subassemblies suitable for these portable device applications include, but are not limited to, Folded Inverted Conformal Antenna (FICA) sub-assemblies, Planar Inverted-F Antenna (PIFA) sub-assemblies, an Inverted-F Antenna (IFA) sub-assemblies, a Folded-J Antenna (FJA) sub-assemblies, a monopole antenna sub-assemblies, and a loop antenna sub-assemblies.
The size of the antenna sub-assembly in portable electronic device, for example, in a mobile phone, constrains the overall size of the device. For example, a FJA sub-assembly used in a candy bar mobile phone and a clam shell mobile phone requires around 13 millimeters (mm) of ground-keep-out area. Similarly, a FICA sub-assembly for some cellular mobile phone applications requires two elongated U-shaped conductors, around 15-20 mm long, depending on the operating frequency. Moreover, some FICA sub-assemblies require clearance distance from certain metallic components, for example, the battery and keypad, to avoid interference. It is challenging to reduce antenna size without sacrificing antenna performance.
The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description and the accompanying drawings described below. The drawings may have been simplified for clarity and are not necessarily drawn to scale.